TWI400353B - The formation of silicon - based thin films and silicon - based films - Google Patents

Description

Method for forming lanthanide film and lanthanide film

The present invention relates to a method for forming a lanthanide film and a lanthanide film. More specifically, the present invention relates to a method of forming a ruthenium-based film having an insulating function or a barrier function by a CVD (Chemical Vapor Deposition) method on a substrate.

The tantalum nitride film is important as a protective film or an insulating film of a semiconductor device, which is formed by a thermal CVD method or a plasma CVD method. For the thermal CVD method, for example, using decane (SiH ₄ ) gas and ammonia (NH ₃ ) gas, the tantalum nitride film is subjected to chemical gas on the surface of the substrate by thermal decomposition reaction at a temperature of 750 ° C to 800 ° C. Phase deposition. In the plasma CVD method, SiH ₄ gas and NH ₃ gas are still used, and a high-frequency electric field is applied to the reaction gas, and the gas is activated by the electrical energy thereof, and is subjected to a plasma reaction at about 300 ° C. At a low temperature, the tantalum nitride film is subjected to chemical vapor deposition on the surface of the substrate. Conventionally, the tantalum nitride film formed in this manner has a problem that cracks or peeling are likely to occur due to intrusion of moisture and impurities.

As a method of forming a tantalum nitride film which is difficult to form by cracking or peeling, for example, Patent Document 1 discloses a technique of etching a substrate surface under vacuum using a halogen-based gas excited by a plasma. Thereby, the impurities remaining on the substrate are completely removed, and homogeneous fine concavities and convexities are formed on the surface to improve the adhesion between the tantalum nitride film and the substrate and the film quality. Further, Patent Document 2 discloses a technique in which a pretreatment chamber is provided in a stage before a film forming chamber, and an ECR (Electron Cyclotron Resonance) plasma is irradiated onto the surface of the substrate in the pretreatment chamber. The moisture contained in the film adsorbed on the surface of the substrate or the film formed on the substrate is desorbed.

[Patent Document 1] Japanese Patent Laid-Open No. Hei 5-315251 (Patent Document 2) Japanese Patent Laid-Open No. Hei 5-331618

However, when the method of the above Patent Document 1 is applied to a substrate on which an electronic component such as an organic EL (Electro Luminescence) is formed, there is a possibility that the electronic component itself is etched. Moreover, when the method of the above-mentioned Patent Document 2 is applied to the above substrate, the electronic component is continuously exposed to the ECR plasma when moisture is removed, and thus is easily damaged by the plasma. Further, since the pretreatment chamber is provided in the front stage of the film forming chamber, the size of the apparatus is increased.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a lanthanoid film and a method for forming the lanthanide film, which can improve the adhesion of the lanthanoid film to the substrate, so that cracking or peeling can be formed. The ruthenium-based film does not cause damage to the electronic components formed on the substrate, and does not increase the size of the device.

In order to achieve the above object, the method for forming a ruthenium-based film of the present invention is a method for forming a ruthenium-based film having an insulating function or a barrier function by a CVD method on a substrate K, which comprises the steps of: using a gas containing hydrogen element And a gas containing a lanthanum element, a step of forming the first thin film 11 by the plasma CVD method on the substrate K, and forming a second by a plasma CVD method using a gas containing a nitrogen element and a gas containing a lanthanum element a step of forming the film 12; and forming a third film 13 by a plasma CVD method using a gas containing oxygen and a gas containing a lanthanum element.

Preferably, the first film 11 is formed on the lowermost layer, and the plurality of second films 12 and the third film 13 are alternately laminated on the first film 11.

More preferably, the second film 12 and the third film 13 are formed in such a manner that the composition ratio of Si, H, C, N, and O contained in the second film is Si:H:C:N:O =1: 3 to 4: 1.5 to 2.5: 0.3 to 1.5: 0.5 or less, and the composition ratio of Si to O contained in the third film 13 is Si: O = 1:1.9 to 2.1.

More preferably, the gas containing ruthenium element used in forming the first film 11, the second film 12, and the third film 13 is HMDS (Hexa-Methyl-DiSilazane, hexamethyldioxane) gas.

Further, the ruthenium-based film of the present invention is characterized in that it is a ruthenium-based film having an insulating function or a barrier function, and the first film 11, the second film 12, and the third film 13 are sequentially laminated on the substrate K, and the first film The constituent elements of the film 11 include H and Si, and the composition ratio of Si, H, C, N, and O contained in the second film 12 is Si:H:C:N:O=1:3~4:1.5~ 2.5: 0.3 to 1.5: 0.5 or less, the composition ratio of Si to O contained in the third film 13 is Si: O = 1:1.9 to 2.1.

Preferably, the first film 11 is formed on the lowermost layer, and the plurality of second films 12 and the third film 13 are alternately laminated on the first film 11.

In the present invention, the substrate is a resin film which is provided with an insulating function or a barrier function, and is a resin film such as a PET (polyethylene terephthalate) film, or an organic EL or the like is formed on the resin film. Component.

According to the present invention, there is provided a bismuth-based film and a method for forming the lanthanide-based film, which can improve the adhesion of the lanthanoid-based film to the substrate, prevent cracking or peeling, and cause damage to electronic components formed on the substrate. And does not make the device large.

Hereinafter, the best mode for carrying out the invention will be described using the accompanying drawings. Fig. 1 is a front schematic view showing a sealing film forming apparatus used in the practice of the present invention, and Fig. 2 is a plan view schematically showing a sealing film forming apparatus shown in Fig. 1. Further, the sealing film forming apparatus is a maker of an experiment for film formation, which is different from a device used in a production line in a semiconductor device manufacturing factory such as an organic EL substrate.

As shown in FIG. 1, the sealing film forming apparatus 1 includes a loading chamber 2, a remote control chamber 3 connected to the loading chamber 2, and a film forming chamber 4 connected to the remote control chamber 3. The sealing film which is the object of formation of the sealing film forming apparatus 1 is a laminated film of a lanthanum nitride film and a yttrium oxide film.

The load chamber 2 can be isolated from the remote control chamber 3 by the gate valve 21. Further, the loading chamber 3 is connected to the vacuum pump 22, and a substrate storage chamber 23 is provided inside. The substrate storage 23 is provided with a support pin 24 for supporting the peripheral portion of the substrate K. Here, the substrate K has a size of 370 mm × 470 mm, and an organic EL element 9 is formed on the surface thereof.

The substrate transfer robot 31 is provided inside the remote control room 3. The substrate transfer robot 31 includes a motor 32, an arm 33, and a movable support table 34. The movable support table 34 is configured to be freely movable in the X, Y, and Z directions via the arm 33 by the driving of the motor 32. The movable support table 34 has the same support pin 35 as the support pin 24 of the substrate storage 23 described above.

The film forming chamber 4 communicates with the remote control chamber 3, and is connected to the vacuum pump 42, the HMDS supply tank 44, the NH ₃ supply tank 46, the H ₂ supply tank 52, the Ar supply tank 53, and the O ₂ supply tank 55. It is connected to the vacuum pump 42 via the flow rate control valve 41, is connected to the HMDS supply tank 44 via the flow rate control valve 43, is connected to the NH ₃ supply tank 46 via the flow rate control valve 45, and is connected to the H ₂ supply tank via the flow rate control valve 51. The 52 and Ar supply tanks 53 are connected to the O ₂ supply tank 55 via the flow rate control valve 54. A loop antenna 47 is provided inside the film forming chamber 4.

The loop antenna 47 is a mechanism for generating plasma, and is constituted by an insulating tube 48 and a conductive electrode 49. The insulating tube 48 is disposed in parallel in the film forming chamber 4 in such a manner that the two insulating tubes 48 are opposed to each other. The electric electrode 49 is inserted into the two insulating tubes 48, and penetrates the opposite side walls of the film forming chamber 4 so as to have a substantially U shape as shown in the top view of FIG. 2, and is connected to a power source for supplying a high frequency current. 50. The frequency of the high frequency current 50 is preferably 13.56 MHz. Further, the plasma to be used may be CCP (Capacitive Coupled Plasma), ICP (Inductive Coupled Plasma), barrier discharge, hollow discharge, or the like.

Next, a method of forming the sealing film of the present invention will be described with reference to Figs. 3 to 8 . 3 and 4 are views for explaining a stage of forming a sealing film of the present invention, FIG. 5 is a flow chart showing a procedure for forming a sealing film of the present invention, and FIG. 6 is a flow chart showing a procedure for forming a first film. 7 is a flow chart showing a procedure for forming a second film, and FIG. 8 is a flow chart showing a procedure for forming a third film.

The sealing film forming apparatus 1 will be described as an initial state shown below. That is, in the load chamber 2, the gate valve 21 is in a closed state, and the internal pressure of the load chamber 2 is atmospheric pressure. In the substrate storage 23, the unsealed substrate K (see FIG. 3(A)) in which the organic EL element 9 is formed on the surface is kept in a state in which the element forming surface K1 is vertically downward. Further, the internal pressures of the film forming chamber 4 and the remote control chamber 3 are reduced to 9.9 × 10 ^-5 Pa or less by the vacuum pump 42.

First, in step S1, the vacuum pump 22 starts to operate to decompress the load chamber 2. When the internal pressure of the load chamber 2 becomes substantially the same as the internal pressure of the film forming chamber 4 and the remote control chamber 3, the gate valve 21 is opened. Next, in step S2, the arm 33 of the substrate transfer robot 31 is extended to the loading chamber 2, and the unsealed substrate K held in the substrate storage 23 is in the same posture, that is, the element forming surface K1 is vertically downward. Received on the movable support table 34. After receiving the substrate K, the arm 33 of the substrate transfer robot 31 contracts. After the arm 33 is contracted, the gate valve 21 is closed, and as shown by a chain line in Fig. 1, the arm 33 of the substrate transfer robot 31 extends to the film forming chamber 4, and the substrate K is placed above the loop antenna 47.

After the substrate K is placed in the film forming chamber 4, the formation process of the first film in the step S3 is started. First, the flow valve 51 is opened to introduce a mixed gas of H ₂ gas and Ar gas into the film forming chamber 4 . At the same time, the flow valve 43 is opened to introduce the HMDS gas into the film forming chamber 4. By introducing Ar gas, the dissociation reaction can be carried out with a plasma of less energy. At this time, the introduction flow rate of each gas is preferably 20 sccm to 40 sccm for the mixed gas of H ₂ gas and Ar gas, and 3 sccm to 5 sccm for the HMDS gas (step S31). If it deviates from the above range, the desired film cannot be obtained, and problems such as film peeling and cracking may occur.

Then, a high frequency current flows from the power source 50 into the loop antenna 47. Thereby, plasma is generated around the loop antenna 47. The plasma power at this time is preferably 5 kW to 10 kW (step S32). The reason is that if the plasma power is less than the above range, the gas ionization caused by the plasma is reduced, the film thickness is reduced, and the film formation time is longer; on the contrary, if the plasma power is larger than the above range, electricity is generated. Etching and sputtering of the slurry reduce the film produced to form a film that is not desired. As shown in FIG. 3(B), a surface reaction is performed on the surface of the substrate K to form the first thin film 11 so as to coat the organic EL element 9. After the lapse of the specific time T1, the flow valve 51 is closed to stop the introduction of the mixed gas of the H ₂ gas and the Ar gas (step S33). The specific time T1 is, for example, the time for producing a film thickness of 15 nm, and is 45 seconds for the device of Fig. 1.

After the first film 11 is formed, the formation process of the second film 12 in the step S4 is started. First, the flow valve 45 is opened to introduce NH ₃ gas into the film forming chamber 4. Further, N ₂ gas may be introduced instead of the NH ₃ gas. At the same time, the introduction flow rate of the HMDS gas is adjusted by the flow valve 43. At this time, the introduction flow rate of each gas is preferably 5 sccm to 500 sccm for the NH ₃ gas and 3 sccm to 20 sccm for the HMDS gas (step S41). If it deviates from the above range, the desired film cannot be obtained, and problems such as film peeling and cracking may occur.

Then, a high-frequency current flows from the power source 50 into the loop antenna 47 so that the plasma power becomes 0.1 kW to 8 kW. The reason is that if the plasma power is less than the above range, the gas ionization caused by the plasma is reduced, the film thickness is reduced, and the film formation time is longer; on the contrary, if the plasma power is larger than the above range, electricity is generated. Etching and sputtering of the slurry reduce the film produced to form a film that is not desired. Thereby, plasma is generated around the loop antenna 47 (step S42). As shown in FIG. 3(C), a surface reaction is performed on the surface of the substrate K to form a second thin film 12, that is, a tantalum nitride film, so as to coat the first thin film 11. After the lapse of the specific time T2, the flow valve 45 is closed to stop the introduction of the NH ₃ gas (step S41). The specific time T2 is, for example, the time for producing a 50 nm film thickness of the tantalum nitride film, and is 2 minutes for the apparatus of Fig. 1. Preferably, the tantalum nitride film has a composition ratio of Si, H, C, N and O, and Si:H:C:N:O=1:3~4:1.5~2.5:0.3~ 1.5: 0.5 or less. Since the chemical formula of HMDS is (CH ₃ ) ₃ SiNHSi(CH ₃ ) ₃ , the HMDS supply tank 44 functions as a supply source of C.

After the second film 12 is formed, the formation process of the third film 13 in the step S5 is started. First, the flow valve 54 is opened to introduce O ₂ gas into the film forming chamber 4. At the same time, the introduction flow rate of the HMDS gas is adjusted by the flow valve 43. At this time, the introduction flow rate of each gas is preferably from 20 sccm to 1000 sccm for the O ₂ gas and from 3 sccm to 20 sccm for the HMDS gas (step S51). If it deviates from the above range, the desired film cannot be obtained, and problems such as film peeling and cracking may occur.

Then, a high-frequency current flows from the power source 50 into the loop antenna 47 so that the plasma power is 0.1 kW to 8 kW. The reason is that if the plasma power is less than the above range, the gas ionization caused by the plasma is reduced, the film thickness is reduced, and the film formation time is longer; on the contrary, if the plasma power is larger than the above range, electricity is generated. Etching and sputtering of the slurry reduce the film produced to form a film that is not desired. Thereby, plasma is generated around the loop antenna 47 (step S52). As shown in FIG. 4(D), a surface reaction is performed on the surface of the substrate K to form a third thin film 13, that is, a hafnium oxide film, so as to coat the second thin film 12. After a certain time T3 has elapsed, the flow valve 54 is closed to stop the introduction of the O ₂ gas (step S53). The time T3 for producing a 100 nm film thickness of the cerium oxide film at a specific time T2 was 2 minutes for the device of Fig. 1. The yttrium oxide film preferably has a composition ratio of Si to O of Si:O = 1:1.9 to 2.1.

The processing of the above steps S4 and S5 is repeated N times (in this example, N=2). As a result, as shown in FIG. 4(F), two layers of a laminate obtained by laminating a yttrium oxide film (third film 13) are formed on the tantalum nitride film (second film 12). As described above, first, the first thin film 11 is formed on the substrate K by the plasma CVD method using H ₂ gas, Ar gas, and HMDS gas as the material gas, and second, NH ₃ gas and HMDS gas are used. The second film 12, which is a tantalum nitride film, is formed on the film 11. Thereafter, the third film 13 which is a ruthenium oxide film is formed on the second film 12 by using O ₂ gas and HMDS gas.

Hereinafter, it is found that the adhesion of the first film 11 formed in the step S3 is good. Specifically, it was evaluated by the tape peeling test described below, and it was confirmed that the adhesion was good: the film was cut into a 10×10 grid such as a checkerboard at intervals of 2 mm, and adhered from above to peel it off. The evaluation stripped a few squares. By inserting the first film 11 between the substrate K and the second film 12, the adhesion between the substrate K and the second film 12 and the film after the second film is improved, and as a result, the second film 12 is less likely to cause turtles. Cracking or peeling, and the phenomenon of uneven performance is reduced and reliable. Further, by alternately laminating the plurality of second thin films 12 and the third thin film 13, it was found that the barrier properties against moisture and oxygen were remarkably improved. The details are described in the Examples section.

The method of the present invention is different from the prior art in that an etching process or the like is not used, so that the electronic component such as the organic EL element 9 is not damaged. Further, the laminated body of the second film 12 and the third film 13 has a function of protecting the electronic component such as the organic EL element 9 from the chemical vapor deposition on the substrate K, and is damaged by the plasma energy, so the plasma energy is applied to the electronic component. Less damage. Further, since the formation of the second film 12 and the formation of the third film 13 are performed in the same chamber (film forming chamber 4), the device structure is not increased in size. Further, since the HMDS gas is used as a material gas, there is no fear of explosion and it is excellent in safety.

In order to prevent the organic EL itself from being thermally damaged on the substrate on which the organic EL device is formed, it is preferred that the temperature at the time of formation of each film is 100 ° C or lower. Further, in the formation of the sealing film described above, the movable support table 34 may be rocked at a specific cycle in the X direction. Thereby, a uniform film in which the unevenness disappears can be formed.

When the laminated body of the Nth second film 12 and the third film 13 is formed and completed (YES in step S6), the gate valve 21 of the load chamber 2 is opened, and the arm 32 of the substrate transfer robot 31 is contracted, and then extended to the loading chamber 2 . Then, the sealed substrate K is transferred to the substrate storage 23, and the arm 33 of the substrate transfer robot 31 is contracted. After the arm 33 is contracted, the gate valve 21 is closed. After the load chamber 2 is returned to the atmospheric pressure and opened in step S6, the substrate K on which the sealing film has been formed can be taken out to the outside in step S9.

[Examples]

Hereinafter, embodiments of the invention will be described. Fig. 9 is a view for explaining the effect of the present invention on the moisture and oxygen trapping of the sealing film.

According to the above-described embodiment, the first film 11 is formed on the PET film substrate, and 10 layers of the tantalum nitride film and the yttrium oxide film are alternately formed thereon, and a total of 21 laminated films are formed, and MOCON is used as a low humidity measurement method. The lower limit of the measured water vapor transmission rate is 0.02 g/m ² . day. If the low water vapor transmission rate is high, the protective property (barrier property) with respect to moisture is high. As a comparative example, a single film of a tantalum nitride film and a single film of a ruthenium oxide film formed on a PET film substrate were also measured by a low humidity measurement method, MOCON method, and the water vapor transmission rate was about 0.15 g. /m ² . Day, so the effect of multi-layering can be fully confirmed.

Further, according to the above-described embodiment, the first thin film 11 is formed on the glass substrate, and a tantalum nitride film and a hafnium oxide film are alternately formed thereon, and a total of five laminated films are formed (state of FIG. 4(F)). RBS (Rutherford Back-Scattering Spectroscopy) was measured, and in the fourth layer close to the atmosphere, a certain amount of oxygen was detected (the ratio of oxygen in the film composition was 1.5%), but it was far from the atmosphere. In the second layer, which is the lower layer, oxygen was not detected at all, and it was found that the protective property against oxygen was excellent. Incidentally, the PET film was produced and the oxygen permeation amount was 0.1 cm ³ /m ² . day.

As described above, the reason why the sealing film formed by the method of the present invention is excellent in moisture and oxygen protection characteristics will be described with reference to FIG. In FIG. 9, when there is a void 131 such as a crack or a non-film-forming portion on the yttrium oxide film (third film) 13, moisture and oxygen in the outside air are blocked on the way as indicated by a solid arrow A1, and thus The bottom layer has not been reached (refer to the dotted arrow A2). This is considered to be because the tantalum nitride film (second film) 12 functions as a water and oxygen trap (capturing mechanism). In other words, it is considered that the lanthanum nitride film 12 adsorbs moisture and oxygen. By increasing the number of layers in the laminate, it is expected that the above effects can be further improved. Further, even if there are no voids 131 such as cracks or non-film-forming portions on the ruthenium oxide film 13, there is moisture and oxygen permeating the film itself, and in this case, moisture and oxygen are caused by the solid arrow A3. The display was blocked on the way and did not reach the bottom layer (refer to the dotted arrow A4).

The embodiments of the present invention have been described above, and the embodiments disclosed above are merely illustrative, and the scope of the present invention is not limited to the embodiments. The scope of the present invention is defined by the scope of the claims, and all modifications in the meaning and scope of the claims are included.

9. . . Organic EL element (electronic component)

11. . . First film

12. . . Second film

13. . . Third film

K. . . Substrate

Fig. 1 is a front schematic view showing a sealing film forming apparatus used in the practice of the present invention.

Fig. 2 is a schematic plan view showing the sealing film forming apparatus of Fig. 1.

3(A), 3(B), and 3(C) are views for explaining the stage of formation of the sealing film of the present invention.

4(D), 4(E), and 4(F) are views for explaining the formation stage of the sealing film of the present invention.

Fig. 5 is a flow chart showing the order of formation of the sealing film of the present invention.

Fig. 6 is a flow chart showing the procedure for forming the first film.

Fig. 7 is a flow chart showing the procedure for forming the second film.

Fig. 8 is a flow chart showing the procedure for forming the third film.

Fig. 9 is a view for explaining the effect of capturing moisture and oxygen in the sealing film of the present invention.

9. . . Organic EL element

11. . . First film

12. . . Second film

13. . . Third film

131. . . Void

K. . . Substrate

Claims (7)

A method for forming a lanthanoid film, which is formed on a substrate by a CVD (Chemical Vapor Deposition) method to form a ruthenium film having an insulating function or a barrier function, and is characterized by comprising the following steps: a gas of a hydrogen element and a gas containing a lanthanum element, a step of forming a first thin film by a plasma CVD method on the substrate; and forming a second by a plasma CVD method using a gas containing a nitrogen element and a gas containing a lanthanum element a step of forming a film; and a step of forming a third film by a plasma CVD method using a gas containing oxygen and a gas containing a lanthanum element. A method of forming a ruthenium-based film according to claim 1, wherein the first film is formed on the lowermost layer, and the plurality of second films and the third film are alternately laminated on the first film. The method for forming a ruthenium-based film according to claim 1 or 2, wherein the second film and the third film are formed in such a manner that a composition ratio of Si, H, C, N and O contained in the second film is Si:H :C:N:O=1:3~4:1.5~2.5:0.3~1.5:0.5 or less, the composition ratio of Si and O contained in the third film is Si:O=1:1.9~2.1. The method for forming a ruthenium-based film according to claim 1 or 2, wherein HMDS (Hexamethyldisilazane, hexamethyldiazide nitrogen) is used as a gas containing ruthenium element used for forming the first film, the second film, and the third film. Alkane gas. A lanthanide film by the lanthanide according to any one of claims 1 to 4 Formed by a method of forming a film. A bismuth-based film having an insulating function or a barrier function, wherein a first film, a second film, and a third film are laminated on a substrate, and the constituent elements of the first film include H and Si, and the second film The composition ratio of Si, H, C, N and O contained in the Si:H:C:N:O=1:3~4:1.5~2.5:0.3~1.5:0.5 or less, Si contained in the third film The composition ratio with O is Si:O=1:1.9~2.1. The ruthenium-based film according to claim 6, wherein the first film is formed on the lowermost layer, and the plurality of second films and the third film are alternately laminated on the first film.